After Shippey's graduation in the early 1960s he did not immediately start an academic career since the British economy of the time did not offer many jobs in academia. Only in the mid-1960s did he enroll at the University of Cambridge from where he graduated with an M.A. in 1968.[4][5] He was awarded a PhD from Cambridge University in 1970.[5]

Shippey became a junior lecturer at the University of Birmingham, and then a Fellow of St John's College, Oxford, where he taught Old and Middle English.[3] In 1979, he was elected to the Chair of English Language and Medieval English Literature at the University of Leeds.

In 1996, after 14 years at Leeds, Shippey was appointed to the Walter J. Ong Chair of Humanities at Saint Louis University's College of Arts and Sciences, where he did teaching, research and publishing. He retired from there in 2008, and now lives in Dorset.[5]

Under the pseudonym of "Tom Allen" he has written two stories that were published in anthologies edited by Peter Weston. The first published was the fantasy story "King, Dragon" in Andromeda 2 in 1977; the second was the science fiction novelette "Not Absolute" in Andromeda 3 in 1978.[6]

In addition to writing books of his own, he has edited both The Oxford Book of Science Fiction Stories, and The Oxford Book of Fantasy Stories and reviews science fiction for the Wall Street Journal.[7] In 2009, he wrote a scholarly 21-page introduction to Flights of Eagles, a collection of James Blish works.[8]

In late 1969 or early 1970, Shippey wrote his first academic work on Tolkien. He then delivered a speech at a Tolkien day organised by a student association. This lecture, "Tolkien as philologist" became also influential for Shippey's view of Tolkien. Joy Hill, Tolkien's private secretary, was in the audience and afterwards she asked him for the script, for Tolkien to read. On 13 April 1970, Shippey received a seemingly formal letter from Tolkien.[3]

The two, Shippey and Tolkien, first met in 1972. Shippey was invited for dinner by Norman Davis who had succeeded Tolkien at the Merton Chair of English Language. When he became a Fellow of St. John's College, Shippey taught Old and Middle English using Tolkien's syllabus.[3]

Shippey's first printed essay, "Creation from Philology in The Lord of the Rings", expanded on his 1970 lecture. In 1979, he was elected into a former position of Tolkien's, the Chair of English Language and Medieval English Literature at Leeds University. His first book, The Road to Middle-earth, was published in 1982. At this time, Shippey shifted from regarding Tolkien as a philologist to a "traumatised author" as he called it. This would include writers affected by war like Vonnegut and Golding.[3]

Shippey appeared in several documentaries about Peter Jackson's The Lord of the Rings film trilogy. The dialect coaches were assisted by him[4] and Shippey received a personal mention in the closing credits.[9] He summarized his experiences with the film project as follows:

"The funny thing about interviews is you never know which bits they're going to pick. It always feels as if they sit you down, shine bright lights in your eyes, and ask you questions until you say something really silly, and that's the bit they choose. At least they didn't waterboard me. But it was good fun, and I'd cheerfully do it again."[10]

Shippey's education and academic career have crossed paths in many ways with those of Tolkien: like Tolkien, he attended King Edward's School in Birmingham and both taught Old English at Oxford University. Shippey also occupied Tolkien's former position at the University of Leeds and was responsible for changing the curriculum that Tolkien himself had instituted.[11]